The invention relates to a composition for dyeing keratin fibers, in particular human keratin fibers such as the hair, comprising, in a medium which is suitable for dyeing, at least one cationic direct dye of given formula and at least one specific thickening polymer. The invention also relates to the dyeing processes and dyeing devices, i.e., kits, using the composition.
Two types of dyeing may be distinguished in the haircare sector. The first is semi-permanent or temporary dyeing, or direct dyeing, which uses dyes capable of giving the hair a natural coloration, a more or less pronounced color change which may withstand shampooing several times. These dyes are also known as direct dyes; they can be used with or without an oxidizing agent. In the presence of an oxidizing agent, the aim is to obtain lightening dyeing. Lightening dyeing is carried out by applying a mixture, prepared at the time of use, of a direct dye and an oxidizing agent to the hair, and makes it possible in particular to obtain, by lightening the melanin in the hair, an advantageous effect such as a unified color in the case of grey hair, or to bring out the color in the case of naturally pigmented hair.
The second is permanent dyeing or oxidation dyeing. This is carried out with so-called xe2x80x9coxidationxe2x80x9d dyes comprising oxidation dye precursors and couplers. Oxidation dye precursors, commonly known as xe2x80x9coxidation basesxe2x80x9d, are compounds which are initially colorless or weakly colored which develop their dyeing power on the hair in the presence of oxidizing agents added at the time of use, leading to the formation of colored compounds and dyes. The formation of these colored compounds and dyes results either from an oxidative condensation of the xe2x80x9coxidation basesxe2x80x9d with themselves or from an oxidative condensation of the oxidation bases with coloration-modifying compounds commonly known as xe2x80x9ccouplersxe2x80x9d, which are generally present in the dye compositions used in oxidation dyeing.
It is known practice to add direct dyes to oxidation dyes in order to vary the shades obtained with the said oxidation dyes or to enrich the shades with glints. Among the cationic direct dyes available in the sector of dyeing keratin fibers, in particular human keratin fibers, the compounds whose structure is developed in the text hereinbelow are already known; nevertheless, these dyes lead to colorations which have characteristics that could still be improved, such as the intensity, the homogeneity of the color distributed along the fiber, in which case the coloration is said to be too selective, and the staying power, in terms of the resistance to the various attacking factors to which the hair may be subjected (light, bad weather, shampooing).
After considerable research conducted in this matter, the present inventors have discovered that it is possible to obtain novel compositions for dyeing keratin fibers which are capable of giving more intense and yet unselective colorations which show good resistance to the various attacking factors to which the hair may be subjected, by combining at least one specific thickening polymer with at least one known cationic direct dye of the prior art, which have the respective formulae defined below. This discovery forms the basis of the present invention.
A first subject of the present invention is thus a composition for dyeing keratin fibers, and in particular human keratin fibers such as the hair, containing, in a medium which is suitable for dyeing, (i) at least one cationic direct dye whose structure corresponds to formulae (I) defined below, characterized in that it also contains (ii) at least one specific thickening polymer.
(i) The cationic direct dye which can be used according to the present invention is a compound of formula (I) below:
Axe2x80x94Nxe2x95x90Nxe2x80x94Bxe2x80x83xe2x80x83(I)
in which:
the symbol A represents a group chosen from the structures A1 to A3 below: 
xe2x80x83in which structures A1 to A3,
R1 denotes a C1-C4 alkyl radical, a phenyl radical which can be substituted with a C1-C4 alkyl radical or a halogen atom chosen from chlorine, bromine, iodine and fluorine;
R2 denotes a C1-C4 alkyl radical or a phenyl radical;
R3 and R4, which may be identical or different, represent a C1-C4 alkyl radical, a phenyl radical or else, in the case of structure A1, can together form a benzene ring substituted with one or more C1-C4 alkyl, C1-C4 alkoxy or NO2 radicals and, in the case of structure A2, can together form a benzene ring optionally substituted with one or more C1-C4 alkyl, C1-C4 alkoxy or NO2 radicals;
R3 can also denote a hydrogen atom;
Z denotes an oxygen or sulphur atom or a group xe2x80x94NR2;
M represents a xe2x80x94CH, xe2x80x94CR (R denoting C1-C4 alkyl) or xe2x80x94N+R5(Xxe2x88x92)r group;
K represents a xe2x80x94CH, xe2x80x94CR (R denoting C1-C4 alkyl) or xe2x80x94N+R5(Xxe2x88x92)r group;
P represents a xe2x80x94CH, xe2x80x94CR (R denoting C1-C4 alkyl) or xe2x80x94N+R5(Xxe2x88x92)r group; r denotes zero or 1;
R5 represents an atom Oxe2x88x92, a C1-C4 alkoxy radical or a C1-C4 alkyl radical;
R6 and R7, which may be identical or different, represent a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C1-C4 alkyl or C1-C4 alkoxy radical or an xe2x80x94NO2 radical;
Xxe2x88x92 represents an anion preferably chosen from chloride, iodide, methyl sulphate, ethyl sulphate, acetate and perchlorate;
with the proviso that,
if R4 denotes a C1-C4 alkyl radical and Z denotes a sulphur atom, R3 does not denote a hydrogen atom; if R5 denotes Oxe2x88x92, then r denotes zero;
if K or P or M denote C1-C4xe2x80x94N+-alkyl Xxe2x88x92, then R6 or R7 is other than a hydrogen atom;
if K denotes xe2x80x94N+R5(Xxe2x88x92)r, then Mxe2x95x90Pxe2x95x90xe2x80x94CH, xe2x80x94CR;
if M denotes xe2x80x94N+R5(Xxe2x88x92)r, then Kxe2x95x90Pxe2x95x90xe2x80x94CH, xe2x80x94CR;
if P denotes xe2x80x94N+R5(Xxe2x88x92)r, then Kxe2x95x90M and denote xe2x80x94CH or xe2x80x94CR;
if Z denotes xe2x80x94NR2 and R2 denotes a C1-C4 alkyl radical, then at least one of the radicals R1, R3 or R4 of the group of structure A2 is other than a C1-C4 alkyl radical;
the symbol B represents:
(a) a group of structure B1 below: 
xe2x80x83in which structure B1,
R8 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C1-C4 alkyl or C1-C4 alkoxy radical, a radical xe2x80x94OH, xe2x80x94NO2, xe2x80x94NHR11, xe2x80x94NR12R13, xe2x80x94NHCO (C1-C4) alkyl, or forms with R9 a 5- or 6-membered ring which may or may not contain one or more hetero atoms chosen from nitrogen, oxygen and sulphur;
R9 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C1-C4 alkyl or C1-C4 alkoxy radical or forms, with R10 or R11, a 5- or 6-membered ring which may or may not contain one or more hetero atoms chosen from nitrogen, oxygen and sulphur;
R10 represents a hydrogen atom, an xe2x80x94OH radical, a radical xe2x80x94NHR11 or a radical xe2x80x94NR12R13;
R11 represents a hydrogen atom, a C1-C4 alkyl radical, a C1-C4 monohydroxyalkyl radical, a C2-C4 polyhydroxyalkyl radical or a phenyl radical;
R12 and R13, which may be identical or different, represent a C1-C4 alkyl radical, a C1-C4 monohydroxyalkyl radical or a C2-C4 polyhydroxyalkyl radical;
(b) a 5- or 6-membered nitrogenous heterocyclic group which can contain other hetero atoms and/or carbonyl groups and which can be substituted with one or more C1-C4 alkyl, amino or phenyl radicals,
and in particular a group of structure B2 below: 
in which structure B2,
R14 and R15, which may be identical or different, represent a hydrogen atom, a C1-C4 alkyl radical or a phenyl radical;
Y denotes the xe2x80x94COxe2x80x94 radical or the radical 
n=0 or 1, with, when n denotes 1, U denoting a xe2x80x94COxe2x80x94 radical.
In the structures defined above, the C1-C4 alkyl or alkoxy group preferably denotes methyl, ethyl, butyl, methoxy or ethoxy.
The cationic direct dyes of formula (I) which can be used in the dye compositions in accordance with the invention are known compounds and are described, for example, in patent applications FR-2,189,006, FR-2,285,851 and FR-2,140,205 and its Certificates of Addition, the disclosure of each of which is specifically incorporated by reference herein.
Among the cationic direct dyes of formula (I) which can be used in the dye compositions in accordance with the invention, mention may be made more particularly of the compounds of structures (I)1 to (I)77 below: 
The cationic direct dye(s) of formula (I) used according to the invention preferably represent(s) from 0.001 to 10% by weight approximately relative to the total weight of the dye composition and even more preferably from 0.005 to 5% by weight approximately relative to this weight.
(ii) The thickening polymer which can be used according to the present invention is a polysaccharide or a cellulose chosen from:
(ii)1xe2x80x94nonionic guar gums;
(ii)2xe2x80x94biopolysaccharide gums of microbial origin, such as scleroglucan gum or xanthan gum;
(ii)3xe2x80x94gums derived from plant exudates, such as gum arabic, ghatti gum, karaya gum, gum tragacanth, carrageenan gum, agar gum and carob gum;
(ii)4xe2x80x94pectins;
(ii)5xe2x80x94alginates;
(ii)6xe2x80x94starches;
(ii)7xe2x80x94carboxyalkylcelluloses.
The nonionic guargums can be modified or unmodified. The unmodified guar gums are, for example, the products sold under the name Vidogum GH 175 by the company Unipectine and under the name Jaguar C by the company Meyhall.
According to the present invention, it is preferred to use nonionic guar gums modified with C1-C6 hydroxyalkyl groups.
Among the hydroxyalkyl groups which may be mentioned, for example, are hydroxymethyl, hydroxyethyl, hydroxypropyl and hydroxybutyl groups. These guar gums are well known in the state of the art and can be prepared, for example, by reacting the corresponding alkene oxides such as, for example, propylene oxides, with guar gum so as to obtain a guar gum modified with hydroxypropyl groups. The degree of hydroxyalkylation, which corresponds to the number of alkylene oxide molecules consumed by the number of free hydroxyl functions present on the guar gum, preferably ranges from 0.4 to 1.2.
Such nonionic guar gums optionally modified with hydroxyalkyl groups are sold, for example, under the trade names Jaguar HP8, Jaguar HP60 and Jaguar HP120, Jaguar DC 293 and Jaguar HP 105 by the company Rhxc3x4ne-Poulenc (Meyhall) or under the name Galactasol 4H4FD2 by the company Aqualon.
The biopolysaccharide gums of microbial origin, such as scleroglucan gum or xanthan gum, the gums derived from plant exudates such as gum arabic, ghatti gum, karaya gum, gum tragacanth, carrageenan gum, agar gum and carob gum, the hydroxyalkylcelluloses and carboxymethylcelluloses, pectins, alginates and starches are well known to those skilled in the art and are described in particular in the book by Robert L. Davidson entitled xe2x80x9cHandbook of Water soluble gums and resinsxe2x80x9d published by McGraw Hill Book Company (1980), the disclosure of which is specifically incorporated by reference herein.
Among these gums, the scleroglucans more particularly used according to the present invention are represented by the products sold under the name Actigum CS by the company Sanofi Bio Industries and in particular Actigum CS 11, and under the name Amigel by the company Alban Muller International. Other scleroglucans, such as the one treated with glyoxal in French patent application No. 2,633,940, the disclosure of which is specifically incorporated by reference herein, can also be used.
The xanthan gums more particularly used according to the present invention are represented by the products sold under the names Keltrol, Keltrol T, Keltrol TF, Keltrol BT, Keltrol RD and Keltrol CG by the company Nutrasweet Kelco, or under the names Rhodicare S and Rhodicare H by the company Rhodia Chimie.
Among the carboxyalkylcelluloses preferably used is carboxymethylcellulose, for which mention may be made of the products sold under the names Blanose 7M8/SF, Blanose Raffinxc3xa9e 7M, Blanose 7LF, Blanose 7MF, Blanose 9M31F, Blanose 12M31XP, Blanose 12M31P, Blanose 9M31XF, Blanose 7H, Blanose 7M31 and Blanose 7H3SXF by the company Aqualon, or Aquasorb A500 and Ambergum 1221 by the company Hercules, or Cellogen HP810A and Cellogen HP6HS9 by the company Montello, or Primellose by the company Avebe.
The thickening polymers (ii) used in the compositions of the present invention are preferably present in a proportion of from 0.01 to 10% by weight approximately, in particular in a proportion of from 0.1 to 5% by weight approximately, relative to the total weight of the dye composition applied to the keratin fibers.
The medium which is suitable for dyeing (or support) generally comprises water or a mixture of water and at least one organic solvent to dissolve the compounds which would not be sufficiently water-soluble. As organic solvents, mention may be made, for example, of C1-C4 lower alkanols such as ethanol and isopropanol; aromatic alcohols such as benzyl alcohol, as well as similar products and mixtures thereof.
The solvents can be present in proportions preferably ranging from 1 to 40% by weight approximately relative to the total weight of the dye composition, and even more preferably from 5 to 30% by weight approximately.
The pH of the dye composition in accordance with the invention is generally approximately ranging from 2 to 11 and preferably approximately ranging from 5 to 10. It can be adjusted to the desired value using acidifying or basifying agents usually used for dyeing keratin fibers.
Among the acidifying agents, mention may be made, by way of example, of inorganic or organic acids such as hydrochloric acid, orthophosphoric acid, sulphuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid and lactic acid, and sulphonic acids.
Among the basifying agents, mention may be made, by way of example, of aqueous ammonia, alkaline carbonates, alkanolamines such as mono-, di- and triethanolamine and derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds of formula (II) below: 
in which W is a propylene residue optionally substituted with a hydroxyl group or a C1-C6 alkyl radical; R16, R17, R18 and R19, which may be identical or different, represent a hydrogen atom or a C1-C6 alkyl or C1-C6 hydroxyalkyl radical.
In addition to the cationic direct dye(s) (i) defined above, the dye composition in accordance with the invention can contain one or more additional direct dyes which can be chosen, for example, from nitrobenzene dyes, anthraquinone dyes, naphthoquinone dyes, triarylmethane dyes, xanthene dyes and azo dyes which are non-cationic.
When it is intended for oxidation dyeing, the dye composition in accordance with the invention contains, in addition to the cationic direct dye(s) (i), one or more oxidation bases chosen from the oxidation bases conventionally used for oxidation dyeing and among which mention may be made in particular of para-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols and heterocyclic bases.
When they are used, the oxidation base(s) preferably represent(s) from 0.0005 to 12% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005 to 6% by weight approximately relative to this weight.
When it is intended for oxidation dyeing, the dye composition in accordance with the invention can also contain, in addition to the cationic direct dye (i) and the thickening polymer (ii) as well as the oxidation bases, one or more couplers so as to modify the shades obtained or to enrich them with glints, by using the cationic direct dye(s) (i) and the oxidation base(s).
The couplers which can be used in the dye composition in accordance with the invention can be chosen from the couplers used conventionally in oxidation dyeing and among which mention may be made in particular of meta-phenylenediamines, meta-aminophenols, meta-diphenols and heterocyclic couplers.
When it is (they are) present, the coupler(s) preferably represent(s) from 0.0001 to 10% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005 to 5% by weight approximately relative to this weight.
The dye composition in accordance with the invention can also contain various adjuvants conventionally used in compositions for dyeing the hair, such as antioxidants, penetrating agents, sequestering agents, fragrances, buffers, dispersing agents, surfactants, film-forming agents, ceramides, preserving agents, screening agents, such as sunscreens, and opacifiers.
Needless to say, a person skilled in the art will take care to select this (these) optional complementary compound(s) such that the advantageous properties intrinsically associated with the dye composition in accordance with the invention are not, or are not substantially, adversely affected by the addition(s) envisaged.
The dye composition according to the invention can be in various forms, such as in the form of liquids, shampoos, creams or gels or any other form which is suitable for dyeing keratin fibers, and in particular human hair. It can be obtained by mixing, at the time of use, a composition, which may be pulverulent, containing the cationic direct dye(s) with a composition containing the specific thickening polymer.
When the combination of the cationic direct dye (i) and the thickening polymer (ii) according to the invention is used in a composition intended for oxidation dyeing (in which case one or more oxidation bases are used, optionally in the presence of one or more couplers) or when it is used in a composition intended for lightening direct dyeing, then the dye composition in accordance with the invention also comprises at least one oxidizing agent chosen, for example, from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulphates, and enzymes such as peroxidases, lactases and two-electron oxidoreductases. It is particularly preferred to use hydrogen peroxide or enzymes.
Another subject of the invention is a process for dyeing keratin fibers, and in particular human keratin fibers such as the hair, using the dye composition as defined above.
According to a first variant of this dyeing process in accordance with the invention, at least one dye composition as defined above is applied to the fibers, for a period which is sufficient to develop the desired coloration, after which the fibers are rinsed, optionally washed with shampoo, rinsed again and dried.
The time required to develop the coloration on the keratin fibers is generally from 3 to 60 minutes and even more specifically from 5 to 40 minutes.
According to a second variant of this dyeing process in accordance with the invention, at least one dye composition as defined above is applied to the fibers, for a period which is sufficient to develop the desired coloration, without final rinsing.
According to one specific embodiment of this dyeing process, and when the dye composition in accordance with the invention comprises at least one oxidation base and at least one oxidizing agent, the dyeing process comprises a first step which comprises separately storing, on the one hand, a composition (A1) comprising, in a medium which is suitable for dyeing, at least one cationic direct dye (i) as defined above and at least one oxidation base, and, on the other hand, a composition (B1) comprising, in a medium which is suitable for dyeing, at least one oxidizing agent, and then in mixing them together at the time of use, after which this mixture is applied to the keratin fibers, the composition (A1) or the composition (B1) containing the thickening polymer (ii) as defined above.
According to another specific embodiment of this dyeing process, and when the dye composition in accordance with the invention comprises at least one oxidizing agent, the dyeing process comprises a first step which comprises separately storing, on the one hand, a composition (A2) comprising, in a medium which is suitable for dyeing, at least one cationic direct dye (i) as defined above, and, on the other hand, a composition (B2) comprising, in a medium which is suitable for dyeing, at least one oxidizing agent, and then in mixing them together at the time of use, after which this mixture is applied to the keratin fibers, the composition (A2) or the composition (B2) containing the thickening polymer as defined above.
Another subject of the invention is a multi-compartment dyeing device, i.e., a dyeing xe2x80x9ckitxe2x80x9d or any other multi-compartment packaging system, a first compartment of which comprises the composition (A1) or (A2) as defined above and a second compartment of which comprises the composition (B1) or (B2) as defined above. These devices can be equipped with means for dispensing the desired mixture onto the hair, such as the devices described in patent FR 2,586,913, the disclosure of which is specifically incorporated by reference herein.
The examples which follow are intended to illustrate the invention without, however, limiting its scope.